From:	"M. Schulter" <mschulter AT value DOT net>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: !!NEGATIVE NUMBERS IN ASM!! Pleez answer.
Date:	19 Feb 1998 04:44:02 GMT
Organization:	Value Net Internetwork Services Inc.
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Message-ID:	<6cgdai$iq6$1@vnetnews.value.net>
References:	<34EB3694 DOT 714183B6 AT mail DOT htk DOT fi> <34EB6330 DOT 2388 AT wpi DOT edu>
NNTP-Posting-Host:	value.net
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

chris doty <orz AT wpi DOT edu> wrote:
: > I just want to know, how I can change a number, which is negative, to
: > positive,
: > and in asm. I bet it can be done, but how?
: >  I've got an almost ready cool demo-effect, but when I add two numbers
: > together,
: > the other one is negative, and I can't do anything about it.

: x86s have hardware support for flipping the sign.  I believe mnemonic is
: NEG.  This is equivelent to a NOT followed by an INC.

Just a note that in one GAS (GNU assembler) program, I used fabs to obtain
the absolute value of a floating-point number. However, I'm not sure if
this program uses floating-point values, and I guess that integer math, if
adequate, might be faster <grin>.

Most respectfully,

Margo Schulter
mschulter AT value DOT net

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